Generally, Passive Optical Networks (“PONs”) included passive optical components, e.g., fibers, splitters and couplers, are provided to guide traffic between a Central Office (“CO”) and remote Optical Network Units (“ONUs”) located at customer premises. The passive optical components are devices that operate to pass or restrict light. The passive optical components do not have electrical power or processing requirements.
A conventional WDM PON performs bi-directional communication by using two different wavelength bands. Downstream optical signals may be transmitted from a Central Office to a remote Optical Network Unit located at a customer's premise through one wavelength band, e.g., in a wavelength range from 1570 nanometers (“nm”) to 1620 nm. Upstream optical signals may be transmitted from the Optical Network Unit to the Central Office through another wavelength band, e.g., in a wavelength range from 1450 nm to 1500 nm. Optical signals are transmitted through a number of discrete wavelength channels that exist in these wavelength bands. For example, the wavelength band to transmit downstream signals may contain sixteen discrete optical channels to carry information from the Central Office to sixteen discrete subscribers. Similarly, another wavelength band to transmit upstream signals may contain another sixteen discrete optical channels to carry information from the sixteen discrete customers to the Central Office.
Using different wavelength channels to transmit data in upstream and downstream directions is typically expensive.
A conventional Time Domain Multiplexing (“TDM”) PON communication between the Central Office and remote ONUs may be performed over a single feeder fiber. In the TDM PON architecture, the same bandwidth is shared between multiple ONUs, and dedicated transmission time slots are granted to each individual ONU, to avoid data collision. In the conventional TDM PONs, one user typically cannot have more bandwidth without decreasing the bandwidth of other users.